1. Field of the Invention
The present invention relates to a vehicle door handle system, and in particular, to a vehicle door handle system that enables a vehicle user""s intention to unlock or lock the door to be recognized in a vehicle smart entry system.
2. Related Art
Conventionally, an arrangement for recognizing a vehicle user""s intention to unlock a door is known from, for example, Japanese Patent Application Laid-open No. 7-189538 wherein a capacitance sensor formed from two parallel sensor wires is disposed within a door handle. A vehicle user""s intention to unlock the door is recognized by a change in capacitance when, for example, the vehicle user""s hand approaches the door handle.
In such a conventional arrangement, there is a possibility that the door might be unintentionally unlocked simply when the vehicle user is near the door handle. In order to avoid deterioration in such a theft prevention feature, it is desirable to accurately recognize the vehicle user""s intention to unlock the vehicle door.
It is an object of the present invention to overcome the above-described drawbacks of the conventional arrangement.
It is also an object of the present invention to provide a vehicle door handle system that accurately recognizes a vehicle user""s intention to unlock or lock the vehicle door.
In order to achieve the above-described objects, in accordance with a first aspect of the present invention, a vehicle door handle system includes a pair of electrodes disposed within an operating handle located on the outer surface side of a door along the longitudinal direction of the vehicle. A detection circuit is connected to the two electrodes and detects a change in capacitance therebetween.
In accordance with this arrangement, since the detection circuit detects a change in capacitance between the pair of electrodes when a vehicle user touches the operating handle, the vehicle user""s intention to unlock or lock the door is accurately recognized.
Furthermore, in accordance with a second aspect of the present invention, a vehicle door handle system includes an operating handle having a handle main body and a cover that covers the outer side of the handle main body. The handle main body and cover are each manufactured from a synthetic resin. A metal frame is fixedly housed between the handle main body and the cover. A detection circuit is installed within the frame. In accordance with this arrangement, the detection circuit is protected by installing it within the metal frame, which is a strength maintaining member for the operating handle.
In accordance with a third aspect of the present invention, the metal frame is one of the electrodes and the other electrode is covered with an insulating coating and affixed to the frame. In accordance with this arrangement, since the frame is used as one of the electrodes, the number of parts is reduced and, moreover, the other electrode can easily be installed.
In accordance with a fourth aspect of the present invention, a vehicle door handle system includes an operating handle having a handle main body and a cover that covers the outer side of the handle main body. The handle main body and cover are each manufactured from a synthetic resin. A pair of electrodes and a base plate are also provided, with the detection circuit being fixedly housed within a recess formed in the handle main body so that the two electrodes are covered with the base plate. The interior of the recess is filled with a potting material so as to embed the two electrodes and the base plate. In accordance with this arrangement, the base plate provided with the detection circuit and the pair of electrodes are easily assembled within the operating handle, and moreover, the water resistance of the base plate and the two electrodes is enhanced.
In accordance with a fifth aspect of the present invention, a vehicle door handle system includes a rigid metal ground plate that is fixed to the handle main body so as to cover the recess and is disposed between the cover and the handle main body. In accordance with this arrangement, no change in capacitance between the two electrodes is detected by the detection circuit as a result of merely touching the surface of the cover, which prevents malfunction and tampering and, moreover, the rigidity of the operating handle is enhanced by the ground plate.
In accordance with a sixth aspect of the present invention, the pair of electrodes, which are formed into the shape of a flat plate, are integrally covered with an insulator. In accordance with this arrangement, the pair of electrodes are easily handled as a compact unit.
In accordance with a seventh aspect of the present invention, a vehicle door handle system includes an operating handle having a handle main body and a cover that covers the outer side of the handle main body. The handle main body and cover are each manufactured from a synthetic resin. A rigid metal ground plate is disposed between the cover and the handle main body and is fixed to the handle main body so as to cover the two electrodes from the cover side. In accordance with this arrangement, no change in capacitance between the two electrodes is detected by the detection circuit as a result of merely touching the surface of the cover, thereby preventing malfunction and tampering and, moreover, the rigidity of the operating handle is enhanced by the ground plate.
Modes for carrying out the present invention are explained below by reference to embodiments of the present invention illustrated in the attached drawings.